Re: [Xen-devel] [PATCH v4 2/2] iommu: add rmrr Xen command line option for misc rmrrs

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 08.05.15 at 22:51, <elena.ufimtseva@xxxxxxxxxx> wrote:
> On Thu, May 07, 2015 at 06:47:12AM +0100, Jan Beulich wrote:
>> >>> Elena Ufimtseva <elena.ufimtseva@xxxxxxxxxx> 05/06/15 6:50 PM >>>
>> >In your proposed second valid case, segment 0001 should be assumed for      
>> > 
>> >second device as its own segment is not specified? 
>> 
>> Exactly. Or (less optimal for the user, but easier to implement) require the 
>> segment
>> number to repeated when non-zero (i.e. only adjust the documentation part 
>> here).
> 
> You mean that when segment is non-zero, just specify it explicitly even
> when duplicating seg number from first sbdf?
> like this:
> rmrr=<addr>=0001:bb:dd.f,0001:bb:dd.f

Yes.

> We can use more general approach when adding extra RMRRs. 
> I cannot find from Intel spec if one RMRR region cannot be shared
> among multiple devices from multiple segments.

This may not be explicitly stated, but is necessarily implied from
the data organization in the ACPI tables: Just check where
segment numbers get conveyed, and compare with where the
BDFs get specified.

Jan


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